Multiple point switch



Nov. 21, 1961 E. B. GRAVES ET AL MULTIPLE POINT SWITCH 8 Sheets-Sheet 1Filed April 9, 1956 U Will a m 5 m 5 W Ha Y N .n r 55 r V R N N0 5 K INN0 4 r Wm r M 4 Filed April 9, 1956 N 1961 E. B. GRAVES ET AL I 3,009,993

MULTIPLE POINT SWITCH 8 Sheets-Sheet 2 rronwe'rs 1961 E. B. GRAVES ET AL3,009,993

MULTIPLE POINT SWITCH Filed April 9, 1956 8 Sheets-Sheet 3 INVENTORS.EDWHRD 5. 604m:

DWI/Y R. HILL. Y Osman d. Tye 980R Nov. 21, 1961 E. B. GRAVES ETALMULTIPLE POINT SWITCH 8 Sheets-Sheet 4 Filed April 9, 1956 NNY 4 O a \lw v N s a 0 La MW min m] arr-onus):

MULTIPLE POINT SWITCH Filed April 9, 1956 8 Sheets-Sheet 5 IN ENTORJ'.

0 wono awn A's lbw/1v HML By Donal-a J1 TYGRGUM 947% Maw avenue-ya Nov.21, 1961 E. B. GRAVES ET AL 3,009,993

MULTIPLE POINT SWITCH Filed April 9, 1956 8 Sheets-Sheet 6 BY Ooh nu: J.77108401? /74 W644; 79m

Nov. 21, 1961 MULTIPLE POINT SWITCH Filed April 9, 1956 8 Sheets-Sheet 77.] I /07Z5 5 29 441/03 H g /06 5 ma I l E. B. GRAVES ETAL 3,009,993 71961 E B. GRAVES ETAL 3,009,993

MULTIPLE POINT swncu 8 Sheets-Sheet 8 Filed April 9, 1956 gym 11.1.004071.13 J. HMflU/FN United States Patent 3,009,993 MULTIPLE POINTSWITCH Edward B. Graves, South Euclid, Edwin R. Hill, Chardon, andDonald S. Thorburn, Willoughhy, Ohio, assignors to Picker X-RayCorporation Waite Manufacturing Division, Inc., Cleveland, Ohio, acorporation of Ohio Filed Apr. 9, 19 56, Ser. No. 577,002 26 Claims.(Cl. 20014) This invention relates to switches and more particularly toan electrical rotary switch for selectively controlling the voltage of acurrent flowing therethrough.

An object of this invention is to provide a switch having a plurality ofinterrelated circuits and contacts whereby diiferent desired voltagesmay be quickly, easily and accurately selected by a person relativelyunskilled in the art of manipulating switches.

Another object of this invention is to provide a rotary switch utilizinga plurality of stators and rotors, some of which have major voltageselection steps and others of which have minor voltage selection stepsbetween their contacts to permit selective uniform voltage increases inthe electricity flowing therethrough.

Still another object of this invention is to provide an electricalrotary switch, comprising a plurality of stators and rotors for uniformregulation of voltage, having but a single control knob by which anoperator may precisely adjust the desired amount of voltage.

Another object of the present invention is to provide an electricalrotary switch characterized by its structural simplicity, the ease ofassembly of its parts, its strong and sturdy nature and its lowmanufacturing cost. Other features of this invention reside in thearrangement and design of the parts for carrying out their appropriatefunctions. I

Further objects of the present invention and certain practicaladvantages will be referred to in, or will be evident from, thefollowing description of three embodiments of the present invention, asillustrated in the accompanying drawings, in which:

FIG. 1 is a top plan view of one form of the operating switch mechanism.

FIG. 2 is a side elevation view of the same with the main drive shaftand control knob removed.

FIG. 3 is a vertical sectional view taken alongthe plane of line 3-3 ofFIG. 1.

FIG. 4 is a sectional view taken along the plane of line 4-4 of FIG. 3.

FIGS. 5 and 6 are enlarged fragmentary views taken along the plane ofline 5-5 of FIG.l, showing the operation of the ratchet wheel anddriving dogs or pawls for rotating one of the rotors.

FIG. 7 is an enlarged vertical cross sectional view taken along theplane of line 77 of FIG. 2.

FIG. 8 is a wiring diagram used in connection with the embodiment of theinvention illustrated in FIGS. 1 to 7.

FIG. 9 is an enlarged central sectional view of another embodiment ofthe present invention.

FIG. 10 is a transverse sectional view on a smaller scale taken alongthe plane of line 10-10 of FIG. 9.

FIG. 11 is a transverse sectional view on a smaller scale taken alongthe plane of line 11-111c-f FIG. 9.

FIG. 12 is an end View on a smaller scale taken along the plane of line1212 of FIG. 9.

(FIG. 13 is a wiring diagram used in connection with the embodiment ofthe invention illustrated in FIGS. 9 to 12.

FIG. 14 is a central vertical sectional view of still another embodimentof the present invention.

FIG.15 is a transverse sectional view on a smaller scale taken along theplane of line l5l5 of FIG. 14.

FIG. 16 is a transverse sectional view on a. smaller scale taken alongthe plane of line 16-16 of FIG. 14.

FIG. 17 is a transverse sectional view on a smaller scale taken alongthe plane of line 1717 of FIG. 14.

FIG. 18 is a view similar to FIG. 15. but showing the rotating arms ofthe minor stator advanced clockwise sub stantially degrees and the rotorof the major stator advanced clockwise one contact.

FIG. 19 is a view similar to FIG. 16 but showing the rotor of the minorstator advanced clockwise five contacts and the entire minor statorrotated clockwise through one indexing position.

FIG. 20 is a wiring diagram used in connection with the embodiment ofthe invention illustrated in FIGS. 14 to 19. i

Before describing in detail the embodiments of the invention hereinshown, it is to be understood that the present invention is not limitedto the structural details or the pan ticular arrangement of parts hereinshown, as devices embodying the present invention may take other forms.It also is to be understood that the phraseology and terminology-hereinused are for purposes of description and not of limitation, as the scopeof the present invention is denoted by the appended claims.

Referring now to the drawings, like reference numerals designate likeparts throughout the various figures. As seen in FIGS. 1 and 2, theswitch includes a generally U-shaped base frame or casing 10a which isof pressed metal or other suitable material. Mutually facing moldedplastic insulating stators 11 and 12 of usual design are provided on theupstanding spaced end portions of the casing. Each of the stators isprovided with a plurality of metallic contacts 1 through 10 arranged ina circle around its circumference and secured thereto. The stators 11and 12 are provided on their inner faces with rotors 15 and 16respectively. The rotors are rotatably scoured to the central hubs 22and 23 of the stators by means of suitable nuts 17 and 18 respectively.Each rotor projects radially outwardly from the center of the stator andis adapted to selectively engage the individual contacts provided on thestator. As best seen in FIGS. 1 and 2 rotor 15 and substantiallyZ-shaped member 19 are splined to shaft 22. The Zshaped member 19 isprovided with an axially projecting arm or pin 20 extending away fromrotor 15 toward stator 12. A hollow axle member 21 is freely supportedfor rotation by means of bolt 22 which projects axially from the hub ofstator 11 in alignment with the central hub of stator 12. The outer endof hollow axle 2-1 is supported for rotation by means of bolt 23 whichprojects from the hub of stator 12. It will be understood that the axle21 is free to rotate independent of rotors 15 and 16.

A driven gear 25 is rigidly mounted upon the hollow axle member 21. Thedriven gear member is provided with an axially extending arm or pin 26which is spaced the same radial distance from the axle 21 as the pin 20provided on the Z-shaped member 19. Pin 26 extends toward member 19 andtravels in the same annular space as pin 20. Thus, both of the pins 20and 26 travel about the same radius and intersect one another duringeach revolution of the rotor 15 or gear 25. For purposes of rotating thedriven gear 25 and axle 21, we have provided a driving gear 27 which isfixedly mounted on a longitudinally extending axle 28 which extendsparallel to the axle member 21 but is spaced laterally therefrom. Theends of the axle 28 are journalled for rotation in the upstanding endportions of the casing 10a. One end of the axle is provided with acontrol knob 29, as seen in FIG. 1, which may be grasped by the operatorfor rotating the switch mechanism. The other end of the axle 28 issecured to the casing 10a by means of an adjustable collar 30. The teethof the driving and driven gears 27 and 25 respectively are in meshingengagement,

as viewed in FIG. 1. Thus, it will be seen that upon rotation of thecontrol knob 29 the axle 28 and driving gear 27 are caused to rotatewith the effect of driving the driven gear 25 which causes the rotormember 15 to rotate about the stator 11 upon intersection of the pins 20and 26. The direction of rotation of member 15 will depend upon whichside of pin 20 is engaged by pin 26. The rotor 15 may thereby beselectively positioned upon any of the circumferentially spaced contacts1 through provided on the stator 11.

For purposes of driving rotor member 16, which is rotatably mounted onthe stator 12, we have provided a ratchet wheel 32 which is rigidlysecured to the hollow axle member 21. Suitable means are providedbetween the ratchet wheel 32 and the rotor 16 for causing the rotationof said rotor. Such means include a U-shaped bracket 33 having one ofits legs 33a secured in tight frictional engagement with rotor 16 bymeans of nut 18 while the other and longer leg 33b of the U-shapedbracket member 33 extends substantially parallel to but spaced from theplane of the ratchet wheel 32, as viewed in FIGS. 1 and 2. The leg 33blies between rotor 16 and ratchet wheel 32. Pivotally secured to theouter face of the longer leg 33b of bracket 33 are a pair of opposed orrightand left-hand acting dogs or pawls 35 and 36 respectively. Eachpawl comprises a substantially L-shaped member, one leg 35a, 36a ofwhich is pivotally secured to the outer face of bracket 33 by means ofpivotal pins 37. The other leg 35b, 36b extends axially outwardly toengage the teeth of the ratchet wheel 32. Each of the pawls is providedwith suitable resilient means which herein takes the form of a coilspring 38 and 39 respectively fastened between the pawls and bracket 33to urge the axially extending leg 35b, 36b of each pawl into engagementwith the teeth of ratchet wheel 32. As seen in FIG. 6, when the ratchetwheel is turned by shaft 21 in a clockwise direction, the right pawl 36is engaged and driven by the ratchet wheel while the left pawl 35 ismerely carried along by bracket 33 and rides over the ratchet wheelteeth. The reverse is true when the ratchet wheel 32 is turned in acounterclockwise direction, as viewed in FIG. 6; then the left pawl 35is driven and the right pawl 36 merely slips over the teeth of ratchetwheel 32. Thus it is seen that rotor 16 may be rotated in eitherdirection simply by turning the control knob 29 which in turn rot-atesdrive gear 27 and driven gear 25 thereby causing ratchet wheel 32 torotate in response to rotation of hollow axle 21; the ratchet wheel 32in turn drives the pawls 35 or 36 depending upon the direction ofrotation. The driving pawl imparts its driving force to the U-shapedbracket 33 through pivotal pin 37 and U-shaped bracket 33 through itsfrictional engagement with the rotor 16 causing said rotor to berotated.

Suitable means are provided for disengaging the driving pawl at aparticular point in the rotation of the rotor 16 while simultaneouslyturning the rotor about stator 11. Such means comprise an axiallyextending bolt or lug 40 which is supported adjacent the hollow axle 21between driven gear 25 and ratchet wheel 32 by means of an L-shapedbracket 41 as best seen in FIG. 2, and rigidly secured to the base ofthe casing 10. The pin is so positioned, in the path of rotation of theparticular driving pawl, that it will engage the inner driving edge ofthe pawl and cause it to swing clear of the driving teeth of the ratchetwheel 32 as seen in FIG. 5. In FIG. 5, the ratchet wheel 32 is drivingin a clockwise direction; thus pawl 36 had been the driving pawl whilepawl 35 was merely carried along. In the position of FIG. 5, the drivingpawl 36 is shown deflected out of the path of the driving teeth of theratchet wheel 32 so that it can no longer drive the bracket 33 and rotor16. Pawl 35, through the provision of resilient spring 38, merely slipsas the teeth of ratchet wheel 32 pass by it. Thus, it is seen that oneof the pawls is driven by the ratchet wheel while the other pawlpassively follows until the driving pawl engages the outstandingprojection pin 40, whereupon it is removed from driving engagement withthe ratchet wheel. Continued rotation of the ratchet wheel causes theother or non-driving pawl to slip as viewed in FIG. 5 to permitcontinued turning of the ratchet wheel without rotating the bracket 33and rotor 16, and at the same time turning rotor 15 about stator 11.

As seen in FIG. 3, the stators are provided with ten equally spacedcircumferentially positioned metal contacts. In the present constructionstator 11 is meant to be the major stator while 12 is the minor stator.The major stator 11 has ten contacts which are major voltage selectionsteps of say 10 volt multiples while minor stator 12 has ten contactswhich are minor voltage selection steps of say 1 volt multiples. Thus,it will be seen that the movement of rotor 15 from one contact to theadjacent contact of major stator 11 exceeds by the value of one minorstep a complete revolution of rotor 16 about the minor stator 12. Theswitch is so designed and the parts so positioned that whenever pins 20and 26 engage one another so as to drive rotor 15 about the major stator11, the driving pawl (35 or 36, whichever it may be) is simultaneouslyin engagement with the projecting pin '40 and is thereby renderedineffective to drive rotor 16 of minor stator 12. It will also beunderstood that when either driving pawl is in engagement with theprojecting pin 40 the rotor 16 is so constructed and positioned as to bein contact with either contact 1 or contact 10' of the minor stator 12.Thus, if it were desired to have a setting of say 25 volts (plus voltageY), the control knob 29 would be rotated so that the pin 26 would engagepin 20 of arm 19 and the rotor 15 advanced two contacts on the majorstator 11 so that a total of 20 volts would flow through the majorstator. At this point rotor 16 would be positioned on the tenth contactof minor stator 12 and would not have moved away from this point due torotation of the control knob since the driving pawl would habe beendisengaged by projecting pin 40. Thus an additional amount of 9 volts isflowing through the minor stator 12 thereby supplying a total of 29volts from the switch. In order to produce the desired voltage of 25volts, the operator would then reverse the direction in which he hadturned control knob 29 so that pin 26 will no longer engage pin 20 andthe rotor 15 of major stator 11 remains in contact with the thirdcontact while the ratchet wheel 32 is in driving engagement with pawl 35so as to rotate rotor 16 in a direction wherein said rotor becomespositioned in engagement with the sixth contact of minor stator 12, toreduce the total voltage flowing from the switch'from 29 to the desirednumber 25. Should it be desired to step the voltage up to 39, thecontrol knob would again be rotated in its original direction therebycausing the opposite pawl 36 to rotate the rotor 16 of minor stator 12until it once again engaged the tenth contact whereupon the pawl wouldbe rendered ineffective by projecting pin 40 and the driving operationwould cease and simultaneously the pin 26 would engage pin 20 and rotor15 of major stator 11 would be advanced to the fourth contact therebyadding 10 volts wherein a combined voltage of 39 would be flowing fromthe switch. All voltages selected by the switch are in addition to theminimum voltage Y from. the transformer.

This particular arrangement is desirable so that the voltage can beincreased by uniform steps and any desired voltage thereby obtained. Itshould be noted that limiting stops 46 and 47 are provided on the topsurface of the major and minor stator members respectively to engagetheir rotors and thereby limit their directional rotation. Thus, therotor of the minor stator could not pass from the tenth contact to thefirst contact without first being rotated in a reverse direction pastthe various other contacts.

As seen in FIG. 4 each outer contact of the major and minor stators isprovided with aligned inner contact grooves and ridges on a contactplate 50 which is simultaneously engaged by a secondary rotor 16::mounted on the shaft 23 by means of suit-able nuts 51. Thus, the currentis fed to the contact plate 50 by means of a feed 50a and selectivelytransferred to the inner rotor 16a, thence through the electricallyconducting shaft 23 to outer rotor 16 and selected contact (1 to 10)into the outlet wire 52 connected to the outer contact. The grooves andridges of contact plate 50 tend to retain the rotor 16 in any selectedposition, rotor arm 16a springing from groove to groove.

In FIG. 8 we have shown a wiring diagram which relates specifically tothe embodiment of the present invention shown in FIGS. 1 through 7. Anautotransformer 139 is connected to a suitable power source by lines 131and 132. The major stator 11 is provided with ten contacts 1, 2, 3, 4,etc., which are major voltage selection steps of say ten volt multiples.Each of the ten contacts 1, 2, 3, 4, etc. has a lead wire respectivelyassociated therewith, so that they may be tapped into theautotransformer at spaced distances to provide a total of ten voltsbetween each of the contacts. The minor stator 12 has ten contacts 1,2', 3, 4, 5, etc, each of which is a minor voltage selection step of sayone volt multiple. Each of the contacts of the minor stator 12 isprovided with a suitable lead line to add one volt for each contact. Asheretofore explained, the major and minor stators are provided withrotors 15 and 16 respectively which selectively engage these variouscontacts of their associated stator. The central pivot of the majorrotor 15 is connected to a load circuit 133 by means of line 134 whilethe central pivot of the minor rotor 16 is connected to said loadcircuit by means of line 135. Obviously, the central pivots of rotors 15and 16 are electrically insulated except for the circuits described. Itwill be understood that the movement of rotor 15 from one contact to theadjacent contact of the major stator 11 exceeds by the value of oneminor step to a complete revolution of the rotor 16 about the minorstator 12. Thus, in the position shown in FIG. 8 wherein the rotor 15 ofthe major stator is positioned on contact 3, *a total of twenty volts(additional to Y) would be flowing through the major stator to the loadcircuit 133 and an additional seven volts would be flowing from theminor stator 12 since rotor 16 is positioned in engagement with contact8. Thus, a total of twenty plus seven or twenty-seven added volts areflowing to the load circuit. This voltage is in addition to the constantvoltage across Y which may be set at any desired amount.

In FIGS. 9 through 13 we have shown a modified embodiment of the presentinvention. Here, a pair of spaced concentric major and minor insulatingstators 60 and 61 respectively are retained in the rigid position shownin FIG. 9 by means of suitable side brackets 62 and 63. The brackets 62and 63' are secured to the ends of the stators by means of screws 64.The major stator 60 in the present embodiment is provided with aplurality of six spaced contacts a1, a2, a3, 114, etc. which arearranged arcuately about a portion of the major stator, as seen in FIG.10. The minor stator 61 in the present embodiment is provided with aplurality of ten contacts b1, b2, b3, b4, etc. which are spaced aboutthe entire circumference of the minor stator. Each of the stators 60 and61 is provided with a shaft 67 and 68 respectively which extend throughthe center of the stators in a rotatable fashion I and eachhas "rigidlysecured thereto main rotors 69 and 70 respectively for engagement withthe sets of contacts a and b respectively as the associated shaftrevolves. Secondary rotors 71 and 72 respectively are positioned withinthe hollow interiors of the stators and have spring arms (see FIG. 12)adapted to engage their respective stop plates 73 and 74 which areprovided with a plurality of grooves and ridges and retain the mainrotors 69 and '70 in any selected contact-engaging position. Theseconclary rotor arms 71 and 72 spring from groove to groove about theirrespective plates 73 and 74, as best seen in FIGS. 9 and 12. One of themain distinguishing features between the present embodiment and thatheretofore described is found in the driving means for rotating therotors about their respective stators. As seen in FIGS. 9 and 10, therotatable shaft 67 of the major stator is provided with a pair ofradially projecting arms 75 and 76 (these arms are constructed of aone-piece member). The arms are spaced 180 degrees apart and each is provided with an outstanding longitudinally extending portion, 75a and 76arespectively, which is covered with a suitable cylindrical resilientmaterial, such as rubber. An identical pair of radially extending arms77 and 78 are rigidly secured to the rotatable shaft 68 of the minorstator. The radially extending arms of the minor stator are providedwith longitudinally extending portions 77a and 78a respectively whichare also covered with suitable resilient rubber material. The resilientportions of the respective pairs of radially extending arms of both themajor and minor stators intercept each other in the plane of line lit-10of FIG. 9, and FIG. 10. A control knob 80 is rigidly connected directlyto the rotatable shaft 68 of the minor stator 61 by means of a centrallylocated drive axle 82. Rotation of the control knob 80 causes theradially extending arms of the minor stator 77 and 78 through theirassociated longitudinally extending portions 77a and 78a to interceptthe arms 75 and 76 and their associated longitudinally extendingportions 75a and 76a of major stator 60 after a maximum rotation ofdegrees. From the position shown in FIG. 10 the minor rotor 70 may bemoved only in a clockwise direction due to a stop 87 on stator 61 whichengages rotor 70 to prevent counterclockwise movement. Stop 88 on majorstator 60 engages rotor 69 to prevent further counterclockwise movementfrom the position of FIG. 10. Thus, it will be seen in FIG. 10 that therotor of the minor stator may be moved through a maximum of 180 degreesin a clockwise direction or past five contacts before the rotor of themajor stator is actuated through the intercepting arms described.

The major stator has six contacts, each of which is a major voltageselection step while the minor stator has ten contacts, each of which isa minor voltage selection step. Hereafter, let it be assumed that eachcontact of the major stator is equivalent to four volts and each contactof the minor stator is equivalent to one volt; in order to advance therotor of the major stator one contact, it would'be required that thearms of the minor stator be advanced from the position as shown in FIG.10 in a.

clockwise direction.

Referring now to FIG. 13, I have shown a wiring diagram which relatesspecifically to the embodiment of the present invention shown in FIGS. 9through 12. An autotransformer 82 is connected to a suitable powersource by lines L1 and L2. The major stator 60 is provided with sixcontacts a1, a2, a3, a4, etc. which are major voltage selection steps ofsay four volt multiples. Each of the six contacts has a lead wire a1,a2, a3, a4, etc. respectively associated therewith and provided with asuitable contact at their free ends so that they may be tapped into theautotransformer at suitable spaced distances so that each adds a totalof four volts from the autotransformer. The minor stator 61 has tencontacts b1, b2, b3, 114, etc. whichare minor voltage selection steps ofsay one volt multiples. Each of the contacts of theminor stator isprovided with a suitable lead line b1, b2, 173',

M, etc. respectively which engage the autotransformer at spaceddistances in such a manner that each of the contacts adds a total of onevolt through its associated line from the ,autotransformer. A fixedvoltage Z is always in circuit and this may be adjusted as desired. Asheretofore explained, the major and minor stators are provided withrotors 69 and 70 respectively which selectively engage the variouscontacts of their respective stators. The central pivot of the majorrotor 60 is connected to a work circuit 83 by means of line 84 while thecentral pivot of the minor rotor 61 is connected to 7 said work circuit83 by means of line 85. It will be understood that the movement of rotor69 from one contact to the adjacent contact of the major stator 60 hasthe same effect as a half revolution of the rotor 70 about the minorstator 61. Thus, in the position of FIG. 13 wherein rotor 69 ispositioned on contact a2 a total of four volts (added to Z) would beflowing through the major stator to the work circuit 83 and anadditional two volts would be flowing through the minor stator 61 sincerotor 70 is positioned in engagement with contact b3. The four voltsflowing through line 84 to the work circuit in addition to the two voltsflowing through line 85 to the work circuit equals six volts (plus Z),being transferred to the work circuit by means of the major and minorstators. It will thus be understood that through the mechanical meansheretofore described, advancing the rotor 70 and associated arms 77 and78 and portions 77a and 78a of the minor stator in a counterclockwisedirection to (:6 contact, as viewed in FIGS. 10 and 13, causes the rotor69 of the major stator to be driven in a clockwise direction so that therotor of the major stator moves to the next contact and thereby addsfour volts.

Referring again to FIGS. '10 and 11, the rotor 70 of the minor stator isin engagement with contact [11 as seen in FIG. 11 while the rotor 69 ofthe major stator is in engagement with its contact number a1 as seen inFIG. 10. As the rotor 70 of the minor stator is caused to rotate in aclockwise direction, as viewed in FIG. 11, it will move to the positionwhere it is in engagement with contact number b before its outstandingportions 77a and 78a engage the outstanding portions 75a and 76a of themajor stator. Upon further clockwise rotation of the rotor of the minorstator the rotor of the major stator will be advanced one contact foreach contact advanced by the rotor of the minor stator. It will beremembered that the rotor of the minor stator gains one volt as itadvances from one contact to another while the rotor of the major statorgains four volts as it advances from one contact to another in thisdirection. it will be understood that regardless of the positioning ofthe rotor of the major stator, it is always possible to rotate the rotor'70 of the minor stator in a counterclockwise direction and therebyreduce up to a total of four volts from that already flowing, if theminor rotor has been advanced at least five contacts from the setting ofFIGS. and 11. Thus, it will be seen that from an initial setting, asseen in FIGS. 10 and 11, the rotor of the minor stator must advanceacross five contacts prior to engaging and advancing the rotor of themajor stator. Since the rotor of the major stator is always inengagement with one of its contacts, any advancement of the rotor of theminor stator is in addition to the voltage of that major step, so thatas the minor rotor is rotated in a clockwise direction as seen in FIG.10, the total voltage from the switches advances from a total of zerovolts flowing to the major stator to one, two, three and four as theminor rotor is advanced until the portion 78a of the minor statorengages portion 75a of the mapor stator: thereafter the major rotor isadvanced along with the minor rotor so that an additional four voltsflow from the major stator and an additional one volt flows from therotor of the minor stator for each additional contact traversed. Fromany setting it is possible to add or subtract four volts by rotating therotor of the minor stator in a clockwise or counterclockwise directionrespectively without affecting the setting of the major rotor. The abovevoltage from the switch are in addition to the minimum transformervoltage Z.

In FIGS.14 through 19 we have shown still another embodiment of thepresent invention. The present embodiment is somewhat similar to thatshown in FIG. 9 with the exception of the minor stator which instead ofbeing fixed, as in FIG. 9, is mounted for rotation relative to itssupporting member under certain circumstances. Here again, a pair ofspaced major and minor insulating stators and 91 respectively aresupported within a U-shaped bracket 92, having upstanding end portions93 and 94. The major stator, rigid with bracket 92, is shown providedwith a plurality of six circumferentially spaced contacts c1, c2, c3,04, etc, as seen in FIG. 15. The minor stator is provided with aplurality of five contacts d1, d2, d3, (I4 and d5 spaced about a portionof the circumference of the stator. The minor stator is provided with apair of outstanding lugs 95 and 96 which are spaced 180 degrees apart onthe outer circumference of said stator. The entire minor stator issecured to the radially extending flange portion 97:: of a hollowcylindrical member 97, by means of screws 98. The cylindrical portion ofmember 97 is contained within the bore of a hollow annular housing 99which in turn is rigidly secured to the upstanding end 94 of bracket 92by means of screws 100. The cylindrical member 97 is provided with ahollow sleeve member 101 which embraces its outer surface. The sleevemember 101 is provided with a plurality of elongated longitudinallyextending grooves 102 which are spaced circumferentially about its outersurface. The grooves 102 are adapted to receive balls 103 contained inbores 104 of the surrounding housing 99. The sleeve member 101 andmember 97 are maintained against axial movement in housing 99 by O-rings141. The balls are spring loaded by means of coil springs 105 which arein turn retained by screws 106. The purpose of the balls is to engagethe grooves 102 of the sleeve 101 and retain the cylindrical member 97and associated minor stator 91 against accidental rotation in housing99. The halls and springs 105 are of such size that a predeterminedforce will overcome the force of the springs and cause the balls to beretracted into the bores 104 and permit the rotation of the minor statorwithin the housing 99. A control knob 103 is connected directly to therotor 105 of the minor stator 91 by means of a centrally located driveshaft 106 which extends through the hollow of the cylindrical member 97.It will be understood that the driving arms associated with the majorand minor stators and their associated rotor construction is identicalto that previously described with regard to FIG. 9. The major stator 90is rigidly secured to the upstanding end portion 93 of the bracket bymeans of screws 107.

Referring now to FIGS. 15 and 16, it will be seen that the rotor 103 ofthe major stator is in engagement with contact c1 of the major stator,as seen in FIG. 15 and the rotor 109 of minor stator 91 is in engagementwith contact all of the minor stator, as seen in FIG. 16. The rotor 108is limited to further counterclockwise movement by stop 140. Uponclockwise rotation of the rotor 109 of the minor stator, it will advanceacross five contacts before its associated longitudinally extendingmembers 110 and 111 engage the members 112 and 113 of the rotor of themajor stator in driving relationship as seen in FIG. 18 to advance therotor 108 of the major stator into engagement with contact 02. At thetime the members 110 and 111 of the minor stator engage the members 112and 113 of the major stator, the rotor 109 of the minor statorsimultaneously engages the upper projecting lug 95 as seen in FIG. 19and causes the entire minor stator to be rotated (overcoming detents102, 103) within the housing 99 from the position shown in FIG. 16 tothat shown in FIG. 19. it will be understood that if the control knob103 is continued to be turned so that rotor 109 is moved in a clockwisedirection, each movement of the rotor of the major stator from onecontact to the next necessitates that the entire minor stator berotated. Upon rotation of the minor stator, balls 103 are caused toindex with the various grooves 108 in sleeve 101. It will be understoodthat the grooves 102 are spaced a circumferential distance about sleeve101, equal to the circumferential spacing of the contacts of the majorstator, so that the grooves 102 will index with the balls 103 at thesame time that the rotor 108 of the major stator engages its respectivecontacts. Thus, the entire minor stator will have different positionsfor each step selected on the major stator. Each voltage step on themajor stator equals n-l times each voltage step on the minor statorwhere n is the number of steps on the minor stator. In this case assumesteps on the minor stator of 2 volts each. Then each step on the majorstator is 8 volts which equals (5-1) times 2 volts. In this constructionof the present embodiment a fewer number of contacts are required on theminor stator than in FIG. 9 and the construction of said stator isthereby somewhat simplified. Comparing FIGS. and 19 it is seen that theentire minor stator has been revolved in a clockwise direction from thatof FIG- 16 to that of FIG. 19 as illustrated most clearly by therelative positions of the lugs 95 and 96. Upon reverseorcounterclockwise rotation the rotor 109 of the minor stator, as seen inFIG. 19, ceases to engage the lug 95 of minor stator 91 and therebypermits engagement of the various contacts of the minor stator in acounterclockwise direction so that the members 110 and 111 of the minorstator rotate through approximately 180 degrees before again engagingthe members 112 and .113 of the major stator, as seen in FIG. 15. Thisengagement occurs simultaneously with the engagement of the rotor 109 ofthe minor stator with the lower lug 96, as seen in FIG. 16, of the minorstator whereby the rotor 108 of the major stator is moved in acounterclockwise direction while the entire minor stator is rotatedwithin the housing 99 back to the position of EEG. 15 wherein stop 140limits further movement. Fixed on shaft 1% is spring arm 127, analogousto arms 71 and 72 of FIG. 9, which engages detent grooves in stop plate128 for each contact position of rotor 109. The force for moving arm 127out of detent 128 is insuificient to overcome detents 102, 1%. Thus,only for each movement of the major rotor from one contact to another,is the entire minor stator caused to index. This particular form of theinvention requires fewer switch contacts and transformer taps than inthe secondly described device and still gives the same number ofselection steps.

Referring now to FIG. wherein I have shown a wiring diagram whichrelates specifically to the ernbodimerit of the present invention shownin FIGS. 14 through 19. An autotransforiner 120 is connected to asuitable power source by lines 121 and 122. The major stator 90 isprovided with six contacts c1, c2, c3, 04, etc., each of which is amajor voltage selection step' of say five volt multiples. Each of thesix contacts has a lead wire 01', c2, 03', etc. associated therewith.Each lead wire is tapped into the autotransformer at suitable spaced distances whereby each adds five volts. The minor stator 91 has fivecontacts d1, d2, d3, d4 and d5, which are minor voltage selection stepsof say one volt multiples. The contacts of minor stator 91 are alsoprovided with a suitable number of lead lines d1, d2, d3, (14' and d5each respectively connecting its associated contact with theautotransformer at spaced distances equal to say one volt intervals.Both the major and minor rotors 90 and 91 respectively are connected bysuitable lines 124 and 125' respectively to a work circuit 126'. It willbe understood that the movement of rotor 108 from one contact to theadjacent contact on the major stator 99 exceeds by the value of oneminor step the movementof the rotor 109 of the minor stator across alllive of its contacts. Thus, the rotor positions seen in FIG. 20 whereinthe rotor 108 positioned on contact c2 supplies a total of five voltsthrough the major stator to the work circuit (plus voltage X). Anadditional four volts is supplied through the minor stator 91 since therotor 199 is positioned in engagement with the con-tact d5. This wouldaccount for nine volts being transferred to the work circuit 126 throughthe major and minor rotors 108 and 109 respectively. This voltage is'inaddition to the constant voltage across X which may, of course, be setat any desired amount.

In View of the foregoing description, taken in con junction with theaccompanying drawing, it is believed that a clear understanding of theconstruction, operation and advantages of the device will be quiteapparent to those skilled in this art.

Having thus described our invention and illustrated its use, what Iclaim is new and desire to secure by Letters Patent is:

1. An electrical switch for uniformly increasing or decreasing the.amount of voltage flowing therethrough, said switch comprising a stator,a plurality of electrical contacts arcuately spaced about said stator, arotor contact pivotally mounted centrally of said stator for movementselectively into engagement with said spaced contacts, driving means,said driving means driving suitable driven means, said driving meansincluding a ratchet wheel, said driven means including a pair of opposedpawls, said pawls being pivotally secured to suitable mounting means,said mounting means in operative driving engagement with said rotorcontact, said pawls operatively engaging said ratchet wheel, said pawlsbeing disposed so that when one is being driven by the ratchet wheel theother passively' follows, whereby to permit driving of said mountingmeans in either direction upon rotation of said ratchet wheel in eitherdirection, and means disposed adjacent said ratchet wheel fordisengaging a driving pawl at a particular point of operation.

2. An electrical switch for uniformly increasing and decreasing theamount of voltage flowing therethrough, said switch comprising a statorand a rotor, said stator having a plurality of circumferentially spacedcontacts, said rotor having a contact for selective engagement with thecontacts of said stator, driving means for rotating said rotor, drivenmeans operatively associated with said rotor, said driven meansincluding a pawl disposed to drive when driven in one direction and topassively follow when driven in the other direction, a second pawlopposed to said first pawl and disposed to drive when said first pawlfollows and follow when said first pawl drives, whereby said rotor maybe driven in either direc tion, and means disengaging the driving pawlat a particular point of rotation.

3. A rotary switch comprising a pair of spaced stators, each of saidstators being provided with a plurality of circumferentially spacedcontacts, a rotor rotatably mounted to each of said stators, drivingmeans associated with said switch, said driving means causing one ofsaid rotors to rotate about a first of said stators, the other of saidrotors being secured to a support bracket, said support bracketrotatably secured to the second of said stators, pawl means pivotallysecured to said support bracket, a ratchet wheel associated with saiddriving means, resilient means urging said pawl means into drivingengagement with said ratchet wheel, said pawl means being disposed so asto'engage said ratchet wheel upon rotation of said ratchet wheel ineither direction.

4. A rotary switch comprisng a pair of spaced stators, each of saidstators being provided with a plurality of circumferentially spacedcontacts, a rotor rotatably mounted to each of said stators, drivingmeans associated with said switch, said driving means causing one ofsaid rotors to rotate about a first of said stators, the other of saidrotors being secured to a support bracket, said support bracketrotatably secured tothe second or" said stators, opposed pawls pivotallysecured to said support bracket, a ratchet wheel associated with saiddriving means, resilient means uring said opposed pawls into drivingengagement with said ratchet wheel, said opposed pawls being disposed sothat when one is being driven by the ratchet wheel the other passivelyfollows, thereby permitting driving the pawls upon rotation of saidratchet wheel in either direction and means disposed adjacent saidratchet wheel for disengaging the driven pawl from said ratchet wheel.

5. A rotary switch comprising a pair of spaced stators,

each of said stators being provided with a plurality ofcircumferentially spaced contacts, a rotor rotatably mounted to each ofsaid stators, driving means associated with said switch, said drivingmeans causing one of said rotors to rotate about a first of saidstators, the other of said rotors being secured to a support bracket,said support bracket rotatably secured to the second of said stators, apair of right and left dogs pivotally secured to said support bracket, aratchet wheel associated with said driving means, resilient means urgingsaid dogs into driving engagement with said ratchet wheel, said dogsbeing disposed so that when one is being driven by the ratchet wheel theother passively follows, thereby permitting driving the dogs uponrotation of said ratchet wheel in either direction and means disposedadjacent said ratchet wheel for disengaging the driven dog from saidratchet wheel.

6. A rotary switch comprising a pair of spaced concentric stators, eachof said stators being provided with a plurality of circumferentiallyspaced electrical contacts, a pair of rotors rotatably mounted one oneach of said stators, each of said rotors having an electrical contactmovable by rotor rotation selectively into engagement with the spacedcontacts of its associated stator, a first of said rotors having anaxially outstanding pin portion, driving means associated with saidswitch, said driving means engaging said outstanding pin portion andcausing said first rotor to rotate about its associated stator, thesecond of said rotors being secured to a support bracket, said supportbracket rotatably secured to a second one of said stators, a ratchetwheel associated with said driving means, a pair of rightand left-handdrive dogs pivotally secured to said support bracket in position toengage said ratchet wheel, resilient means urging said dogs into drivenengagement with said ratchet wheel, said dogs being disposed so thatwhen one is being driven by the ratchet wheel the other passivelyfollows, thereby permitting driving one or the other of said dogs uponrotation of said ratchet wheel in either direction, and means disposedadjacent said ratchet wheel for disengaging the driven dog from saidratchet wheel whenever said driving means engages said projecting pin.

7. A rotary electrical switch for controlling the amount of voltageflowing therethrough, said switch comprising a pair of spaced stators,each of said stators having a plurality of contacts thereon, a firstrotor rotatably secured to a first of said stators and adapted toselectively engage the contacts of said first stator, driving meanscausing said first rotor to rotate, a pair of opposed pawls adapted toalternately engage said driving engagement in driven engagement, supportmeans retaining said pawls, said support means rotatably secured to thesecond of said stators, a second rotor contact secured to said supportmeans and adapted to selectively engage the contacts of said secondstator, said pawls being disposed so that when one is being driven bysaid driving means the other passively follows, thereby permittingdriving said second rotor in either direction.

8. A rotary electrical switch for controlling the amount of voltageflowing therethrough, said switch comprising a drive shaft, said driveshaft having a driving gear mounted thereon, a pair of spaced stators,each of said stators having a plurality of contacts thereon, a drivenshaft supported between said stators, a driven gear rigidly secured tosaid driven shaft, said driven gear engaging said driving gear, a firstrotor rotatably secured to said first stator and adapted to selectivelyengage the contacts of said first stator, said driven gear engaging saidrotor and causing said first rotor to rotate, a ratchet wheel secured tosaid driven shaft, a pair of opposed pawls adapted to alternately engagesaid ratchet wheel, support means retaining said pawls, said supportmeans rotatably secured to the second of said stators, a second rotorfrictionally engaging said support means and adapted to selectivelyengage upon rotation the contacts of said second stator, said pawlsbeing disposed so that when one is being driven by said ratchet wheelthe other passively follows, thereby permitting driving said supportmeans and second rotor upon rotation of said ratchet wheel in eitherdirection.

9. A rotary electrical switch for controlling the amount of voltageflowing therethrough, said switch comprising a drive shaft, said driveshaft having a control knob and a driving gear mounted thereon, a pairof spaced stators positioned adjacent said drive shaft, each of saidstators having a plurality of contacts thereon, a driven shaftassociated with the first of said stators, a driven gear rigidly securedto said driven shaft, said driven gear in meshing engagement with saiddriving gear, a first rotor contact rotatably secured to said firststator and adapted to selectively engage the contacts of said firststator, a projecting pin provided on said first rotor, a projecting pinprovided on said driven gear, said arm and pin being located in the samecircumferential path of travel and engaging one another upon rotation ofsaid driven gear, said driven gear thereby causing said first rotor torotate, a ratchet wheel rigidly secured to said driven shaft, a pair ofopposed pawls adapted to alternately engage said ratchet wheel in drivenengagement, support means pivot-ally retaining said pawls, said supportmeans rotatably secured to the second of said stators, a second rotorcontact frictionally engaging said support means and adapted toselectively engage upon rotation the contacts of said second stator,said pawls being disposed so that when one is being driven by saidratchet wheel the other passively follows, thereby permitting drivingsaid support means and second rotor upon rotation of said ratchet wheelin either direction and means disposed adjacent said ratchet wheel fordisengaging the driven pawl from said ratchet wheel whenever saidprojecting pin and arm engage each other.

10. An electrical rotary switch comprising a pair of spaced concentricstators, a support bracket, the first of said stators being a majorstator mounted stationary upon said support bracket, the second of saidstators being a minor stator and mounted for independent rotation onsaid support bracket, said major stator having a plurality of spacedcontacts arranged about its entire circumference, said minor statorhaving a plurality of spaced contacts arranged about a portion of itscircumference, a rotor contactor mounted for rotation on each of saidstators selectively into engagement with said associated spacedcontacts, driving means for rotating one of said rotor contaotors aboutits associated stator, each of said rotors having a pair of outstandingradially spaced arms associated therewith, the arm of said rotorsadapted to engage and drive one another in either direction duringrotation and means on said minor stator whereby said minor stator isrotated within its supporting bracket upon selective movement of therotor contactor on said major stator from one contact to another, saidmeans so positioned on said minor stator to permit engagement of therotor contactor of said minor stator with each of its associatedcontacts prior to movement of the rotor contactor of the major stator inanother direction.

11. The combination of claim 10 including resilient detent means forreleasably holding said minor rotor contactor in position engaging eachof said minor stator contacts, releasable detent means for holding saidminor stator in various indexed positions relative to its supportingbracket, and the holding power of said first named detent means beingless than the holding power of said last named detent means.

12. An electrical rotary switch comprising a pair of spaced concentricstators, a support bracket, the first of said stators mounted stationaryupon said support bracket, the second of said stators mounted forindependent rotation on said support bracket, said first stator having aplurality of spaced contacts arranged about its circumference, saidsecond stator having a plurality of spaced contacts arranged about itscircumference, a rotor contactor mounted 'for rotation on each of saidstators selectively into engagement with said spaced contacts, drivingmeans for rotating one of said rotor contactors about its associatedstator, each of said rotors having a pair of outstanding radially spacedarms associated therewith, the arms of said rotors adapted to engage anddrive one another in either direction during rotation, and means wherebysaid secondstator is rotated within its supporting bracket uponselective movement of the rotor cont-actors on said first stator fromone contact to another, said means permitting engagement of the rotorcontact of said second stator with each of its associated contacts priorto movement of the rotor contactors of said first stator in anotherdirection.

13. An electrical rotary switch comprising a pair of spaced concentricstators, the first of said stators being stationary, the second of saidstators being mounted for independent rotation, said first stator havinga plurality of spaced contacts arranged about its circumference, saidsecond stator having a plurality of spaced contacts, a rotor contactormounted for rotation on each of said stators selectively into engagementwith said spaced contacts, driving meansfor rotating one of said rotorcontactors about its associated stator, each of said rotors having apair of outstanding radially spaced arms associated therewith, the armsof said rotors adapted to engage and drive one another in eitherdirection during rotation and means whereby said second stator isrotated within its supporting bracket upon selective movement of therotor contactor on said first stator from one contact to another, saidmeans permitting engagement of the rotor contactor of said second statorwith each of its associated contacts prior to movement of the rotorcontactor of said first stator in another direction.

14. An electrical rotary switch comprising a pair of spaced concentricstators, a support bracket, the first of said stators mounted stationaryupon said support bracket, the second of said stators mounted forindependent rotation on said support bracket, said first stator having aplurality of spaced contacts arranged about its circumference, saidsecond stator having a plurality of spaced contacts arranged about itscircumference, a rotor cont actor mounted for rotation on each of saidstators selec tively into engagement with said associated spacedcontacts, driving means for rotating one of said rotor contactors aboutits associated stator, each of said rotors having a pair of outstandingradially spaced arms associated therewith, the arms of said rotorsadapted to engage and drive one another in either direction duringrotation and means whereby said second stator is rotated within itssupporting bracket upon selective movement of the rotor contactor onsaid first stator from one contact to another, said means permittingengagement of the rotor contactor of said second stator with each of itsassociated contacts prior to movement of the rotor contactor of saidfirst stator in another direction.

15. An electrical rotary switch comprising a' pair of spaced concentricstators, the first of said stators being stationary, the second of saidstators being mounted for independent rotation, said first stator havinga plurality of spaced contacts arranged about its circumference, saidsecond stator having a plurality of spaced contacts, a rotor contactormounted for rotation on each of said stators selectively into engagementwith said associated spaced contacts, driving means for rotating one ofsaid rotor contactors about its associated stator, each of said rotorshaving a pair of outstanding radially spaced arms associated therewith,the arms of said rotors adapted to engage and drive one another ineither direction during rotation and means whereby said second stator isrotated within its supporting bnacket upon selective movement of therotor contactor on said first stator from one contact to another.

16. An electrical rotary switch comprising a pair of spaced concentricstators, the first of said stators being stationary, the second of saidstators being mounted for independent rotation, said first stator havinga plurality of spaced contacts arranged about its circumference, saidsecond stator having a plurality of spaced contacts, a rotor contactormounted for rotation on each of said stators selectively into engagementwith said associated spaced contacts, driving means for rotating saidrotor cont actors about their associated stators in either clockwise orcounterclockwise direction, said driving means comprising a pair ofoutstanding radially spaced arms associated with each of said rotors,the arms of said rotors adapted to engage and drive one another ineither direction during rotation, and means rotating said second statoron said support bracket upon selective movement of the rotor contactoron said first stator from one contactor to another, said meanspermitting engagement of the rotor contactor of said second stator witheach of its associated contacts prior to movement of the rotor contactorof said first stator in another direction.

17. An electrical rotary switch comprising a pair of spaced concentricstators, a support bracket, the first of said stators mounted stationaryupon said support bracket, the second of said stators mounted forindependent rotation on said support bracket, said first stator having aplurality of spaced contacts arranged about its circumference, saidsecond stator having a plurality of spaced contacts arranged about itscircumference, a rotor contactor mounted for rotation on each of saidstators selectively into engagement with said associated spacedcontacts, driving means for rotating said rotor contactors about theirassociated stators in either clockwise or counterclockwise direction,said driving means comprising a pair of outstanding radially spaced armsassociated with each of said rotors, the arms of said rotors adapted toengage and drive one another in either direction during rotation, andmeans rotating said second stator on said support bracket upon selectivemovement of the rotor contactor on said first stator from one contact toanother, said means permitting engagement of the rotor contactor of saidsecond stator with each of its associated contacts prior to movement ofthe rotor contactor of said first stator in another direction.

18, An electrical rotary switch comprising a pair of spaced concentricstators, the first of said statorshaving a plurality of spaced contactsarranged about its entire circumference, the second of said statorshaving spaced contacts arranged about only a portion of itscircumference, said second stator mounted for rotation in a supportingbracket, a rotor contactor mounted for rotation on each of said statorsselectively into engagement with said associated spaced contacts,driving means for rotating one of said rotor contactors, each of saidrotors having a pair or outstanding radially spaced arms associatedtherewith, the arms of said rotors adapted to engage and drive oneanother in either direction during rotation and means associated betweensaid stators whereby said second stator is rotated within its supportingbracket upon selective movement of the rotor contactor on said firststator from one contact to another.

19. An electrical rotary switch comprising a frame mounting at least apair of stators in predetermined spaced relation, each of said statorsbeing provided with a plurality of circu-mferentially spaced stationarycontacts, one of said stators having contacts connected for equal minorvoltage selection steps, the other of said stators having contactsconnected for equal major voltage selection steps, a rotor rotatablymounted adjacent each of said stators and having at least one contactthereon for selectively engaging with the stationary contacts on thestator associated therewith, a shaft operatively connected with said oneof said rotors, means for rotatably driving said shaft and said onerotor, and a connection between said rotors permitting a rotatingmovement of said one rotor to continuously drive said other of saidrotors and carry the contact of the latter into engagement with any oneof the contacts on the stator associated therewith,

said connection also permitting said one rotor to be rotatedindependently of said other rotor after said other rotor is positionedto engagement with said any one of the contacts on the associated statorso as to carry the contact on the said one rotor into preselectedengagement with the contacts on the stator associated with the same.

20. An electrical rotary switch as defined in claim 19 and wherein theconnection between said rotor includes means effective to limit theindependent movement of the said one rotor corresponding to the positionoccupied by the said other rotor.

21. An electrical rotary switch as defined in claim 19 and wherein theconnection between said rotors is operative to permit a rotatablemovement of said one rotor in one direction to drive the other of saidrotors in the same direction, said connection also permitting said onerotor to be rotated in the opposite direction independently of saidother rotor.

22. An electrical rotary switch as defined in claim 21 and wherein saidconnection is further characterized by having means operative to limitthe oppositely directed movement of said one rotor correspondingly tothe position occupied by the said other rotor.

23. An electrical rotary switch comprising a frame mounting at least apair of stators in predetermined spaced relation, each of said statorsbeing provided with a plurality of circumferentially spaced stationarycontacts, a rotor rotatably mounted adjacent each of said stators andhaving at least one contact thereon for selectively engaging with thestationary contacts on the stator associated therewith, a shaftoperatively connected with one of said rotors, means for rotatablydriving said shaft and said one rotor, and a connection between saidrotors comprising at least one arm operatively connected with each ofsaid rotors being drivingly engageable one with the other in response toa rotatable movement of said one rotor effective to drive the other ofsaid rotors and carry the contact of the latter into engagement with apreselected one of the contacts on the stator associated therewith, saidconnection also permitting said one rotor to be rotated independently ofsaid other rotor as to carry the contact on the former into preselectedengagement with the contacts on the stator associated with the sme.

24. An electrical rotary switch comprising a frame mounting at least apair of stators in predetermined spaced relation, each of said statorsbeing provided with a plurality of circum ferentially spaced stationarycontacts, a rotor rotatably mounted adjacent each of said stators andhaving at least one contact thereon for selectively engaging with thestationary contacts on the stator associated therewith, a shafitoperatively connected with one of said rotors, means for rotatabflydriving said shaft and said one rotor, and a connection between saidrotors comprising a pair of arms on each of said rotors being drivinglyengageable with each other in response to a rotatable movement of saidone rotor in one direction to drive the other of said rotors in the samedirection and carry the contact of the latter into engagement with apreselected one of the contacts on the stator associated therewith, saidarms being disengageable in response to a rotatable movement of said onerotor in the opposite direction efiective to permit an independentmovement of the latter to carry its contact into preselected engagementwith the contacts on the stator associated with the same.

25. An electrical rotary switch as defined in claim 24 and wherein saidarms are moved into re-engagement with each other in response to apredetermined movement of said one rotor in the opposite direction andeffective to cause the rota-table actuation of said other rotor in saidlatter direction.

26. A rotary switch comprising a pair of spaced stators, each of saidstators being provided with a plurality of circumferential ly spacedcontacts, a first of said stators having contacts connected for equalminor voltage selection steps, the second of said stators havingcontacts connected for equal rnajor voltage selection steps, a rotorrotatably mounted concentric to each of said stators, each of saidrotors having at least one contact thereon for selectively engaging withthe stationary contacts of the stator associated therewith, drivingmeans associated with said rotors and including a connection betweensaid rotors permitting a rotating movement of the first rotor tocontinuously drive the second rotor and carry the contact of said secondrotor into engagement with any one of the contacts on the statorassociated therewith, said connection also permitting the first rotor tobe rotated independently of said second rotor after the second rotor ispositioned to said any one of the contacts on the secondary stator so asto carry the contact of said first rotor into pre-selected engagementwith the contacts on the stator associated with the same.

References Cited in the file of this patent UNITED STATES PATENTS394,568 Griscom Dec. 18, 1888 580,929 Colgate Apr. 20, 1897 941,362Dearborn Nov. 30, 1909 1,452,857 Uphofif Apr. 24, 1923 1,973,630 JohnsonSept. 11, 1934 2,023,894 Leinenweber Dec. 10, 1935 2,089,701 LindermanAug. 10, 1937 2,118,081 Grisdale May 24, 1938 2,456,010 Miller Dec. 14,1948 2,797,271 Augustine June 25, 1957 2,811,594 Papouschek Oct. 29,1957 2,816,183 Mangel Dec. 10, 1957 2,843,822 Scott July 15, 1958

